The term abnāʾ means literally "sons" and is used to refer to several groups. It applies most prominently in a technical sense to two groups. The earlier usage denotes the descendants of the Sāsānian force dispatched to Yemen in the middle of the sixth century C.E. After conquering the area the warriors settled down and started families. These abnāʾ converted to Islam shortly after the rise of Muḥammad, and al-Ṭabarī (d. 310/923) mentions them in his Taʾrīkh (2:1971). For ʿAbbāsid studies, the more usual use of